Substance abuse during pregnancy is expected to have a high long-term cost to society. The magnitude of those costs have yet to be fully quantified. The goal of the proposed research is to identify and quantify a wider range of costs and assess the extent to which alternative treatments are effective in reducing those costs. Criticism of much cost-effectiveness research has been that it demonstrates effectiveness only for those who choose that program, but does not indicate whether it could be effectively applied to other populations. This study builds on an ongoing randomized trial in order to reduce the problem of self-selection. Our primary study population includes women enrolled in the MOM'S project, operated by the Washington State Division of Alcohol and Substance Abuse. Women are randomized into three types of treatment intensive outpatient; short term residential combined with intensive outpatient; and a control group which consists of treatment in other community programs. Additional comparison groups include (1) chemically dependent pregnant women who are identified at delivery through a CSAP project entitled Birth to 3, having received no substance abuse treatment during pregnancy; and (2) pregnant substance abusers who receive treatment through other publicly-funded treatment programs. For each of these groups we will identify the number and cost of different services received during pregnancy through three years post- partum. Secondary databases maintained by the state will identify outcomes and costs associated with use of income assistance, medical assistance, mental health services, child protective services, foster care, employment history, and felony convictions, among others. We will compare the prenatal cost of MOM'S treatment and other programs, with post-partum costs to determine public cost-savings associated with alternative treatment modalities. For specific outcomes we will use multivariate regression techniques to determine the effectiveness of treatment characteristics across modalities. The cost-effectiveness of alternative treatment components with respect to the desired outcome will then be determined. The proposed study will make a substantial contribution to the literature on cost-benefit and cost-effectiveness of substance abuse treatment of chemically dependent pregnant women by quantifying public cost-savings associated with alternative prenatal treatment modalities, and identifying which services are cost-effective at producing the desired outcomes.